Cancer patients experience physical and psychological symptoms, and supportive care needs, which are often under-recognized by clinicians. Unidentified symptoms and concerns can result in treatment interference, poor satisfaction, compromised health-related quality of life (HRQoL), and taxed healthcare systems. Cancer care organizations have emphasized the need for symptom assessment and management within quality cancer care delivery. The Commission on Cancer requires that accredited centers (caring for >70% of U.S. cancer patients) implement universal psychosocial distress screening and make appropriate referrals to psychosocial services. With that impetus, we leveraged health information technology to pilot the Oncology Symptom Screening Initiative (OSSI): a demonstration program where patients complete Patient Reported Outcomes Measurement Information System computer adaptive tests assessing depression, anxiety, fatigue, pain, and physical function, along with checklists of supportive care needs, within the electronic health record (EHR) in select Medical Oncology clinics. Assessment results immediately populate the EHR; severe symptoms and endorsed supportive care needs trigger notifications to clinicians who can then make necessary referrals and care decisions in real time. This seamless EHR integration allows for assimilation into clinical workflows. However, the OSSI is limited to (a) medical oncology patients at one Northwestern Medicine location, and (b) patients who access the patient portal (~30% of our population). This study leverages our expertise in measurement and implementation science, symptom screening and management, and cancer care delivery to accomplish the following aims: Aim 1. Use the Framework for Spread to guide expansion and implementation of the OSSI to reach patients at all Northwestern Medicine cancer clinics. Implementation outcomes will include: acceptability, adoption, appropriateness, feasibility, fidelity, penetration, and sustainability; Aim 2. Evaluate the impact of system-wide implementation of the OSSI on patient and system outcomes over 12 months via (a) a quality improvement study (estimated n=4,000 cases) to compare the impact of the OSSI (versus usual care) on EHR-documented health care usage and patient satisfaction using a stepped wedge design in which clusters of study sites will gradually and randomly be assigned to cross from serving as a control to implementing the OSSI and (b) a human subjects substudy (n=1,000) with patients who will complete the OSSI and PRO measures of health care usage and satisfaction at baseline, 6 & 12 months. We will examine differences in PROs between participants whose OSSI responses trigger clinical alerts and those who do not. We will also explore longitudinal trajectories of PRO scores; Aim 3. Identify implementation facilitators and barriers to system-wide expansion of the OSSI. We will conduct qualitative research to gather feedback from clinicians, administrators, and patients participating in the OSSI expansion (ns=30, 10, & 50, respectively). This will include multiple assessments throughout implementation.